Since you closed the other thread while I was adding an extra reply, I'll post it here so you can still see it :)

Another page that will be your friend is http://www.steamgifts.com/bundle-games
Any game on that list has been Bundled (or sold at more than 90% off) before. This means regardless what you have paid for them now, you will only get (if I remember right) 15% of their steam value. Just so when you make a giveaway you aren't shocked as to why you didn't get full value :)